And another popular Linux distribution pushes a new release out the door. This time around, it's openSUSE, as they just released version 12.1. Other than the usual latest and greatest version of all the open source desktops and associated tools, there's a few other interesting tidbits in this release as well.

No. There really isn't one. I think you meant " one most chose by desktop/server GNU/Linux distros to be the default". We've gone from EXT2 to Reiser 3 to Ext3 to XFS to Ext4, as the sweet spot moves for different situations. BTRFS looks good, but the benchmarks have yet to catch up to ext4 for most tests. Sure it has some compelling features which will make it nice for some applications, but a "default" would have to be best for most situations. Which BTRFS is defiantly not right now and to reach that might require some compromise for other io workloads. You just never really know where one is headed performance wise, until it reaches production level readiness and people start relying on certain performance quirks.

I've gone from ext2, to ext3 to ext4, Seems pretty sane to me.

Ext2 was released the same year as NTFS and there have been 5 versions of that since it was released.

BTRFS can't even fsck yet so i wouldn't worry about it defaulting on distros yet.